The measurement of the strong coupling constant \(\alpha _s(M_Z)\)  from precision data on deep–inelastic scattering
is one of the cleanest ways to obtain this fundamental parameter of the Standard Model. The present world data
allow measurements of \(\delta \alpha _s(M_Z)/\alpha _s(M_Z)\)  at the level of \(\sim O(1\%)\) , [1]}, [2]}, [3]}. In the standard analyses one is fitting the scaling violations of deep–inelastic structure
functions and obtains \(\alpha _s(M_Z)\)  together with the parameters of the parton distribution functions, observing
the correlation of all parameters, cf. [4]}. Compared to this, the measurement of \(\alpha _s(M_Z)\) 
from \(R_{e^+e^-}\) , cf. [5]}, does not need to fit a larger amount of further parameters.
The different precision determinations of \(\alpha _s(M_Z)\)  using different processes do not yet agree and further
precision measurements are therefore needed.
